They are one of the best sources of omega-3 fatty acids in nature, for those who do not eat fish it is the best source of supplement. Improve vision and sleep quality. Mono-polyunsaturated fatty acids help lower "bad" cholesterol and are good for the heart. They contain copper, which is essential for bone health, phosphorus, manganese, vitamin E and vitamin B6, which helps with proper nerve function. Walnuts are rich in antioxidants and healthy fats, can improve brain function and enhance memory.